1. Field of the Invention
This invention relates to an earphone system. More specifically, the present invention relates to an earphone system that provides compatibility to earphones so that the earphones can be connected to a mobile device.
2. Description of the Related Art
Mobile devices, such as mobile communication devices, Personal Digital Assistants (PDAs), etc., are widely used because the mobile devices are easily carried and because the mobile devices provide a variety of functions. Mobile communication devices are equipped with a mobile communication module that is configured to communicate with other devices via a base station so as to transmit and/or receive voice and data information. PDAs are designed to include central processing units (CPUs), memory devices, an Operating System (OS), applications configured to operate with the OS, and function modules, etc. PDAs are configured to perform a variety of functions, such as the collection, the creation, the search and the storage of information.
Functions associated with file playback (e.g., the playback of an audio file), or call transmission are functions that output audio signals. For example, the audio signals may be signals that the mobile device receives from external systems. The audio signals may also be generated by the mobile device when the mobile device plays back a stored audio file. As another example, the audio signals may be generated when the mobile device communicates during a voice transmission. Although audio signals are generally output via a speaker, some mobile device users use earphones to ensure the audio sound has better clarity, or to prevent the audio sound from being shared with others in the surrounding environment.
Mobile devices are equipped with an earphone interface (e.g., plug) that is configured to accept a variety of jacks for earphones (i.e., earphone jacks). Earphone interfaces may be designed in various types according to the various sizes of earphone jacks. Although earphone jacks are designed to be the same size, earphone jacks may have different features. This design variation is reflected in the configuration of the earphone interfaces. For example, an earphone interface may be designed to support 3- or 4-pole earphones according to the number of poles (contacts) in the earphone jack. In addition, although earphone interfaces are manufactured with the same number of poles, the design of earphone interfaces differ in order to support a variety of earphones each of which may have earphone jacks that are designed differently based on the geographical region in which the earphones are sold. For example, earphones sold in US and European markets differ from each other in arrangement of the poles of the jacks, and thus such variation in the arrangement of the poles of the earphone jacks necessitates an earphone interface design which interfaces with the variety of different earphone jacks. Therefore, because conventional earphone interfaces for mobile devices must be designed according to the various types of earphone jacks, manufacturers have difficulty in manufacturing mobile devices. In particular, when mobile device users have earphones compatible with the earphone interfaces of the mobile devices, the users are unable to use them.